Plate Heat Exchanger Selection: A Must-Read Guide for Engineers
Plate heat exchangers are widely used in industrial waste heat recovery and HVAC due to their high efficiency and compactness. However, improper selection leads to insufficient heat transfer, excessive pressure drop or shortened service life. This article summarizes 5 core parameters to help you complete accurate selection quickly.
Parameter 1: Heat Load
Heat load Q is the basis of selection, in kW or MW. Calculation formula:
Q = m x Cp x dT
Where: m is mass flow (kg/s), Cp is specific heat (kJ/kg.C), dT is inlet-outlet temperature difference (C).
We recommend a 10%-15% margin in actual selection to handle operating fluctuations.
Parameter 2: Flow Rate and Velocity
Inter-plate velocity is generally controlled at 0.3-0.8 m/s: too low (<0.2 m/s) tends to foul and lose efficiency; too high (>1.0 m/s) causes excessive pressure loss. Calculate the inter-plate flow area from the allowable velocity and nozzle size.
Parameter 3: Temperature Parameters (inlet/outlet)
Four temperatures must be defined: hot-side inlet, hot-side outlet, cold-side inlet, cold-side outlet.
Note: Counter-flow gives the highest heat transfer efficiency; design the hot and cold fluids to flow counter to each other. The cold-side outlet temperature must not exceed the hot-side inlet temperature (violating the second law of thermodynamics).
Parameter 4: Allowable Pressure Drop
Pressure drop is a constraint in selection. General reference values:
- Water side: allowable pressure drop 0.05-0.1 MPa
- Steam side: allowable pressure drop 0.02-0.05 MPa
- Medium with higher viscosity: allowable pressure drop may be relaxed appropriately
When pressure drop is too high, increase the number of plates or reduce velocity.
Parameter 5: Material Selection
| Service Condition | Recommended Material |
|---|---|
| Ordinary softened water, temperature <100C | 304 stainless steel |
| Water containing chloride ions or corrosive | 316L stainless steel |
| Food / pharmaceutical | 316L + electropolishing |
| Strongly corrosive media (acid, chloride) | Titanium or Hastelloy |
| High-temperature thermal oil (>180C) | All-welded 316L |
Quick Selection Mnemonic
Determine heat load -> choose flow and velocity -> check temperature difference -> verify pressure drop -> confirm material. Five steps, no mistakes.
Need help with heat exchanger selection? Use our online selection calculator; enter parameters to get recommended results, or contact us for a professional selection report (free).